Real Simple answers your questions.

Q. Why does my front-loading washing machine smell like mildew?
Kelly Mearns
Westerly, Rhode Island

A. You’re probably using too much soap.

“Front-loading machines use a third of the water that top loaders do,” says Harry Grubbs, the owner of Mr. Appliance, a repair company in Houston. “If you throw in the same heaping capful of detergent that you would use with a top loader, there won’t be enough water to absorb all the suds.” Soapy residue will then stick to the rubber rim of the door, where it can spawn mildew.

The first line of defense is to use a high-efficiency (HE) detergent, which is effective in small doses and made specifically for front loaders. Next, “check to see if your machine is level,” says James C. Dolbeare Sr., the president of AAA Appliance Service Center, in Chicago. If the floorboards under the machine have warped, it might not be draining properly. A repairman can place antishake pads under the machine to prevent shifting. Another possible culprit: liquid fabric softener. Its waxy base adheres to the outer tub, which “makes it a breeding ground for mildew,” says Grubbs. If you use softener, add the smallest recommended amount, he suggests.

To get rid of the mildew odor, run an empty machine on the hottest setting with bleach or Affresh ($8,, a cleaner that deodorizes a washer’s interior. And after each load of laundry, leave the door ajar to allow the interior to dry.

Watch this video for more tips on getting rid of mildew in your washing machine.